CVE-2026-23354: x86/fred: Correct speculative safety in fred_extint()

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-03-25 · updated 2026-06-17
Weakness: CWE-129

Description

In the Linux kernel, the following vulnerability has been resolved: x86/fred: Correct speculative safety in fred_extint() array_index_nospec() is no use if the result gets spilled to the stack, as it makes the believed safe-under-speculation value subject to memory predictions. For all practical purposes, this means array_index_nospec() must be used in the expression that accesses the array. As the code currently stands, it's the wrong side of irqentry_enter(), and 'index' is put into %ebp across the function call. Remove the index variable and reposition array_index_nospec(), so it's calculated immediately before the array access.

Affected products

Linux kernel: from 6.9.1 before 6.12.77; from 6.13 before 6.18.17; from 6.19 before 6.19.7; 6.9, 7.0-rc1, 7.0-rc2, 7.0-rc3, 7.0-rc4, 7.0-rc5 (+2) — fixed in 6.12.77, 6.18.17, 6.19.7

How to fix

Upgrade to a fixed version: Linux kernel 6.12.77, 6.18.17, 6.19.7. Check the vendor advisory for mitigations.

References

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